The present invention generally relates to bodily fluid sampling devices and more specifically, but not exclusively, concerns a bodily fluid sampling device configured to evaluate the amount of bodily fluid emerged from a rupture on the surface of skin and determine whether the amount is sufficient or insufficient for testing without the need to move the device.
The acquisition and testing of bodily fluids is useful for many purposes, and continues to grow in importance for use in medical diagnosis and treatment, and in other diverse applications. In the medical field, it is desirable for lay operators to perform tests routinely, quickly and reproducibly outside of a laboratory setting, with rapid results and a readout of the resulting test information. Testing can be performed on various bodily fluids, and for certain applications is particularly related to the testing of blood and/or interstitial fluid. Such fluids can be tested for a variety of characteristics of the fluid, or analytes contained in the fluid, in order to identify a medical condition, determine therapeutic responses, assess the progress of treatment, and the like. The fingertip is frequently used as a fluid source because it is highly vascularized and therefore produces a good quantity of blood. However, the fingertip also has a large concentration of nerve endings, and lancing the fingertip can therefore be painful. Alternate sampling sites, such as the palm of the hand, forearm, earlobe and the like, may be useful for sampling, and are less painful. However, they also produce less blood when lanced, thereby increasing the likelihood of that the collected blood sample will be insufficient for accurate test results. For example, if the fluid sample is drawn from the skin onto a test strip prior to the emergence of a sufficient quantity on the skin, the test strip has to be discarded because the test strip is unable to accurately analyze the fluid. Typically, the user then has to lance another site in order to attempt to obtain another sample of fluid. As should be appreciated, this can make monitoring unnecessarily painful as well as expensive.
Sampling devices have been proposed to detect body fluid on the surface of the skin, but these devices still have a number of drawbacks that have prevented the implementation of this fluid detection feature into a successful commercial product. For instance, although these devices are able to alert the user when a sufficient amount of fluid is present on the skin, these sampling devices do not take any actions to automatically increase the amount of fluid when the amount is insufficient. Further, these sampling devices only alert the user when a sufficient amount of fluid is present, and fail to alert the user of fluid insufficiency. By failing to positively alert the user of the fluid insufficiency can make the user question whether the sampling system is working properly. As a result, the user may prematurely remove the sampling device to check its progress before a sufficient amount of fluid can bleed from the incision. Once the device is removed from the skin, automatic fluid collection is practically impossible due to the misalignment created between the incision and the sampling device when the user places the device again over the incision site. Thus, there remains a need for improvement in this field.